Process for manufacturing thin film transistor

Abstract

Disclosed is a process for manufacturing a thin film transistor, the process comprising the steps of providing an oxide semiconductor precursor solution for an oxide semiconductor layer in which an oxide semiconductor precursor is dissolved in a solvent, coating the oxide semiconductor precursor solution on a substrate to form an oxide semiconductor precursor layer, patterning the oxide semiconductor precursor layer so that the oxide semiconductor precursor layer remains at portions where the oxide semiconductor layer is to be formed, and heating the remaining oxide semiconductor precursor layer to form the oxide semiconductor layer.

1 . A process for manufacturing a thin film transistor, the process comprising the steps of:
 providing an oxide semiconductor precursor solution for an oxide semiconductor layer in which the oxide semiconductor precursor is dissolved in a solvent;   coating the oxide semiconductor precursor solution on a substrate to form an oxide semiconductor precursor layer;   patterning the oxide semiconductor precursor layer so that the oxide semiconductor precursor layer remains at portions where the oxide semiconductor layer is to be formed; and   heating the remaining oxide semiconductor precursor layer to form the oxide semiconductor layer.   
   
   
       2 . The process of  claim 1 , wherein the solvent is at least one selected from the group consisting of water, ethanol, propanol, ethylene glycol, tetrahydrofuran, dioxane, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, diethylene glycol monomethyl ether, acetonitrile, xylene, toluene, o-dichlorobenzene, nitrobenzene, meta-cresol, hexane, cyclohexane, tridecane, α-terpineol, chloroform, 1,2-dichloroethane, N-methylpyrrolidone and carbon disulfide. 
   
   
       3 . The process of  claim 1 , wherein the solvent contains 50% or more by weight of water or 50% by weight or more of an alcohol. 
   
   
       4 . The process of  claim 1 , wherein the coating is carried out according to a spin coating method, a spray coating method, a blade coating method, a dip coating method, a cast coating method, a bar coating method, a die coating method, letterpress printing, intaglio printing, lithographic printing, screen printing or ink jetting. 
   
   
       5 . The process of  claim 1 , wherein the patterning comprises employing an ink jet method, a screen printing method, an ablation method or a photoresist method. 
   
   
       6 . The process of  claim 1 , wherein the patterning comprises the steps of forming a photoresist layer on the oxide semiconductor precursor layer; pattern-wise exposing the photoresist layer; and developing the exposed photoresist layer with a developing solution so that the photoresist layer on the oxide semiconductor precursor layer at portions where the oxide semiconductor layer is to be formed remains unremoved and an unnecessary oxide semiconductor precursor layer is removed during development. 
   
   
       7 . The process of  claim 6 , wherein the photoresist layer is formed from a negative working photoresist, a positive working photoresist or a laser-sensitive photoresist. 
   
   
       8 . The process of  claim 6 , wherein the developing solution contains 50% or more by weight of water or 50% by weight or more of alcohol. 
   
   
       9 . The process of  claim 6 , after the heating, further comprising the step of removing the remaining photoresist layer with a solution containing at least one selected from the group consisting of alcohols, ethers, esters, ketones and glycol ethers. 
   
   
       10 . The process of  claim 9 , wherein the solution contains ketones. 
   
   
       11 . The process of  claim 1 , wherein the heating is carried out employing at least one selected from an infrared heater, an electric oven, a dry heat block and a microwave. 
   
   
       12 . The process of  claim 1 , wherein the heating is carried out according to at least irradiation of microwave with a frequency of from 0.3 to 50 GHz. 
   
   
       13 . The process of  claim 1 , wherein the oxide semiconductor precursor comprises a metal ion of In, Sn or Zn. 
   
   
       14 . The process of  claim 1 , wherein the oxide semiconductor precursor comprises a metal ion of Ga or Al. 
   
   
       15 . The process of  claim 1 , wherein the oxide semiconductor precursor comprises at least one metal salt selected from the group consisting of a metal nitrate, a metal sulfate, a metal phosphate, a metal carbonate, a metal acetate and a metal oxalate. 
   
   
       16 . The process of  claim 15 , wherein the oxide semiconductor precursor comprises a metal nitrate. 
   
   
       17 . The process of  claim 1 , wherein the oxide semiconductor precursor solution contains metal A, metal B, and metal C so as to satisfy the following formula, metal A:metal B:metal C=1:0.2 to 1.5:0 to 5 (by mole) wherein metal A denotes a metal contained in a metal salt selected from indium salts and tin salts; metal B denotes a metal contained in a metal salt selected from gallium salts and aluminum salts; and metal C denotes a metal contained in a metal salt selected from zinc salts. 
   
   
       18 . The process of  claim 17 , wherein the metal A is indium, the metal B is gallium, and the metal C is zinc. 
   
   
       19 . The process of  claim 1 , wherein the oxide semiconductor precursor comprises indium nitrate, gallium nitrate and zinc nitrate, the solvent contains 50% by weight or more of water or 50% by weight or more of alcohol, and the heating is carried out according to irradiation of microwave with a frequency of from 0.3 to 50 GHz. 
   
   
       20 . The process of  claim 19 , wherein the solvent contains 50% by weight or more of water.